Mustang history

There is definitely no web site and, as Andrew said, you are unlikely to get much (any?) help from any DMV (Department of Motor Vehicles) office. If you have a former owner's name you might be able to find them (Google possibly?) and contact them to see if they can supply any information but that depends upon them even wanting to talk to you to begin with. If the former owner was John Smith you might well be out of luck trying to find which one of the thousands of possibilities it might be though.

The Google route was how I located the person who sold me my Ivy66GT in 1982. I had his name from the previous title and I actually found a genealogy site with the owner's family history saying he used to live in the town where I bought the car. Even then it took 6 months for them to answer my e-mail request. Unfortunately, he bought the car from a used car lot outside Fort Ord, CA, in the mid 70s so I am unlikely to ever find a prior owner. Finding whoever ran that lot, having them still be alive and having them have any records is almost beyond the possible. A car that has only been through private sales since new would be easier provided the people involved are still alive.